Microsoft Corp and the FBI, aided by authorities in more than 80 countries, have launched a major assault on one of the world's biggest cybercrime rings, believed to have stolen more than $500m (£323m) from bank accounts over the past 18 months.
Microsoft said its digital crimes unit had successfully taken down at least 1,000 of an estimated 1,400 malicious computer networks known as the Citadel botnets.
Citadel infected as many as 5m PCs around the world and, according to Microsoft, was used to steal from dozens of financial institutions, including American Express, Bank of America, Citigroup, Credit Suisse, PayPal, HSBC, JPMorgan Chase, Royal Bank of Canada and Wells Fargo.